Selected from the 1578 Obras de Musica published by blind keyboard master Antonio de Cabezon's son Hernando, these glosas enrich the vast resource of Renaissance vocal music through variation and elaboration. Extra layers of polyphony and ornament crystallize the tradition of improvisation on pre-existing works, both in the splendour of the sacred, and in chansons and madrigals with more secular emotions. Antonio de Cabezon's Tientos y Glosados can be heard on Naxos 8.554836, and Glen Wilson's acclaimed recording of his complete Tientos and Variationsis on 8.572475-76.